The invention relates to a macrocell and a method for adding. Macrocells can be used as functional units for processing data in, for example, microprocessors, controllers or co-processors. Macrocells can be used for building blocks like register files, multiplexers, arithmetic logic units (ALU) and shifters. A central processing unit (CPU) uses data paths for the interconnection of all functional units for processing data. Usual CPUs have data paths of a width of 8, 16 or 32 bits. In the field of crypto processors for public key cryptography calculating units for long number calculating are required. Crypto processors for public key cryptography, for example, may require arithmetic and logic units of a width of at least several hundred bits in order to enable the desired calculation speed in a range of milliseconds. This, in turn, poses a high effort in design, verification and layout of such units.